Username or Email Address
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    VWVortex


    Results 1 to 24 of 24

    Thread: R19 -vs- R30 insulation.

    1. 03-28-2009 12:37 PM #1
      Insulation experts!

      I've been renovating parts of my home over the last year, and am finally rounding third base on my kitchen/dining room.

      Over the ajoined rooms is a vaulted ceiling. (No attic...just your ceiling joists with insulation between them, and your roof) The drywall was cracked and there were some leaks in the roof, so I went ahead and removed all the old drywall and fixed the leaks, etc. Now, before I replace the ceiling, I've got all the insulation exposed and I've noticed that it's R-19.

      Would it be worth replacing the R-19 with R-30? It's about 5-600 square feet of vaulted ceiling. So if my calculations are correct we're talking around 200 bucks and about a half days work?

      Am I wasting a Sunday and 200 bucks?

      Also, if I do go with the R-30, would it be worth taking all the old R-19 and layering it up in the attic over the existing insulation?

      Thanks in advance. I'll post pics in a mega renovation thread when I'm all done with everything.


    2. Member jerk's Avatar
      Join Date
      Aug 28th, 2000
      Location
      Idaho
      Posts
      14,855
      03-28-2009 01:15 PM #2
      I'm no insulation expert, but I think $200 sounds pretty cheap in the grand scheme of things. You're getting a much higher R value and you're there already. As far as re-using your R19 over existing insulation, I don't know.

    3. Senior Member spockcat's Avatar
      Join Date
      Jun 4th, 2003
      Location
      West Coast FL
      Posts
      28,503
      Vehicles
      07 Z4MC, 11 328i Touring, 13 F150 STX 5.0, Versys
      03-28-2009 04:24 PM #3
      Is the R-19 still in good shape; not crushed or collapsed? Would there still be enough space for both R-19 and R-30 in the same cavity, and leave space for air venting? I believe crushing the insulation together decreases it R value. So if R-19 is designed for 3 1/2" and R-30 is designed for 5 1/2", and you still need an inch or so for ventilation of the plywood, you need to have at least 10" rafters. Do you have that?

    4. 03-28-2009 05:24 PM #4
      Quote, originally posted by spockcat »
      Is the R-19 still in good shape; not crushed or collapsed? Would there still be enough space for both R-19 and R-30 in the same cavity, and leave space for air venting? I believe crushing the insulation together decreases it R value. So if R-19 is designed for 3 1/2" and R-30 is designed for 5 1/2", and you still need an inch or so for ventilation of the plywood, you need to have at least 10" rafters. Do you have that?

      the R-19 appears to be in *okay* shape. Some of the backing has become a little brittle and has peeled off, but overall, it's not too bad.

      I just got back from HD, and now I know why they went with R-19. The ceiling joists are only 2x6's with 1" ferring(sp?) strips....so 7" total depth. The R-19 is 6.5" thick, the R-30 is 9.5" thick.....so yeah, to your point, to get R-30 in there, you'd have to compress it, which could completely void any additional benefit?????

      I think I'll just patch up any strips of the R-19 that look bad, as long as I have easy access, and I'll live with it.


    5. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-28-2009 10:33 PM #5
      foam. worth it in the long run.
      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    6. 03-28-2009 11:59 PM #6
      Quote, originally posted by InSaNeBoY »
      foam. worth it in the long run.

      Might be, but if you're talking about the spray-in foam, it won't work in this application. I'm dealing with cathederal ceilings, not a traditional attic. I need something I can staple up and then cover with drywall or ceiling panels, etc.


    7. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-29-2009 09:30 AM #7
      this will be drywalled one day...

      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    8. 03-29-2009 10:17 AM #8
      Whoa...

      More details, please!

      Is it a DIY type project? How expensive is it? How is it installed, etc, etc, etc...


    9. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-29-2009 02:35 PM #9
      I had an insulation contractor put it in, it's not cheap and not a good DIY. doing my whole house was $5k *but* I used to burn 1200gal of oil a year, now we're down to 550gal. So it's well worth the cost
      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    10. Member DiscoStu's Avatar
      Join Date
      May 8th, 2001
      Location
      MA
      Posts
      5,993
      Vehicles
      2010/VW/Passat - 2009/VW/Jetta/Sportwagen
      03-29-2009 02:39 PM #10
      That vaulted ceiling is apparently unvented with the spary foam. Did you use closed cell or open cell.

      I have a very similar application and I'm trying to dig through the information. I was quoted 2" of closed cell, then 4" of open cell to save money.

      The closed cell is really expensive, but it acts like a vapor barrier whereas the open cell does not.

      I wasn't sure if you could put open cell foam in an unvented application without some sort of a vapor barrier.


    11. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-29-2009 05:25 PM #11
      Mine is icynene foam, most climates you don't need a vapor barrier, and a low vapor permeable paint is enough for northern climates (Canada).

      I did want to do closed cell, but the cost was a bit more than i could handle, and found the icynene was more air quality friendly. got a toddler in the house, didn't need to be putting something in that would give off nasty fumes for a while. If I were building new or doing a full rehab and not moving in for a while than I'd do closed cell as it would have time outgas fully before I moved in

      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    12. 03-29-2009 05:48 PM #12
      Quote, originally posted by InSaNeBoY »
      I had an insulation contractor put it in, it's not cheap and not a good DIY. doing my whole house was $5k *but* I used to burn 1200gal of oil a year, now we're down to 550gal. So it's well worth the cost

      It's probably not going to fall within my budget, but thankyou for sharing. I didn't even know that this option existed.

      I think if this was the home I planned on living the rest of my years in, I'd definitely consider it, though.


    13. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-29-2009 05:57 PM #13
      I look at it this way, at the time oil was over $4/gal (it'll end up there again in the not too distant future I'll bet) so I'm saving $2,400/yr at that rate so it'll pay for its self in just over two years... at the current $2/gal figure little over 4 years.

      and it can only be put in when the ceiling is opened so now is your chance.

      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    14. 03-29-2009 08:14 PM #14
      I would do whatever you can do to get a R30 or even a R40 up there. I live very close to your latitude and just made the jump from 20 to 40 (R) and it is incredible. Warmer in the winter...cooler in the summer. The payback will be there as long as you own the house.

    15. 03-29-2009 08:33 PM #15
      Quote, originally posted by InSaNeBoY »
      I look at it this way, at the time oil was over $4/gal (it'll end up there again in the not too distant future I'll bet) so I'm saving $2,400/yr at that rate so it'll pay for its self in just over two years... at the current $2/gal figure little over 4 years.

      and it can only be put in when the ceiling is opened so now is your chance.

      Do you remember what they charged per sq. foot??


    16. Member Phrost's Avatar
      Join Date
      Mar 8th, 2004
      Location
      Green Bay, WI
      Posts
      5,067
      Vehicles
      '11 Audi S4
      03-29-2009 11:43 PM #16
      You do not want compress fiberglass if you only have 7" of space to work with. The air pockets in the insulation is needed for the fiberglass to do it's job, so if you push 9.5" rolls into a 7" space your end result will not be R-30. I'm not sure how much insulating value you lose (since 2.5" extra is not that much), but I think the cost/time of replacing all of it compared to the energy savings will not be worth it.


      Modified by Phrost at 10:44 PM 3-29-2009

    17. 03-30-2009 08:36 AM #17
      Quote, originally posted by Phrost »
      You do not want compress fiberglass if you only have 7" of space to work with. The air pockets in the insulation is needed for the fiberglass to do it's job, so if you push 9.5" rolls into a 7" space your end result will not be R-30. I'm not sure how much insulating value you lose (since 2.5" extra is not that much), but I think the cost/time of replacing all of it compared to the energy savings will not be worth it.


      It would definitely be more convenient to go with this philosophy....

      I wonder if there's anyone on here that would know if this theory is valid?

      Anyone?

      I'm probably not going to realistically start with hanging a ceiling for another week or two, so I've got time.


    18. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-30-2009 10:00 AM #18
      Quote, originally posted by thesteve »

      Do you remember what they charged per sq. foot??

      go online, search 'foam insulation + your area' call a few places and get estimates.

      given the state of the economy I bet you'll get it cheaper than i did (plus prices will vary by area, I know I paid a bit more than one of our clients did in upstate NY)


      Modified by InSaNeBoY at 10:01 AM 3-30-2009

      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    19. Member peecee's Avatar
      Join Date
      Sep 28th, 2005
      Location
      Davidsonville, MD
      Posts
      5,940
      03-30-2009 11:57 AM #19
      Quote, originally posted by thesteve »

      It would definitely be more convenient to go with this philosophy....

      I wonder if there's anyone on here that would know if this theory is valid?

      Anyone?

      I'm probably not going to realistically start with hanging a ceiling for another week or two, so I've got time.

      Insulation is designed to fit a specific joist space. Insulation relies as much on air pockets as the small flecks of glass to prevent air movement. Your best bet is to go perpendicular to the current insulation with as thick you can as possible, leaving the existing R-19 in place. You definitely do not want to stack insulation, and if you can't do the new insulation perpendicular, you should remove the R-19, and add furring strips to bring the current joists out to the full 9.5" R-30 depth.

      If I were you, I'd sister 2x4's onto the existing ceiling joists and put R-30 in. Remove the R-19 and put it somewhere else.


      Modified by peecee at 11:59 AM 3-30-2009


    20. 03-30-2009 02:30 PM #20
      Quote, originally posted by InSaNeBoY »

      go online, search 'foam insulation + your area' call a few places and get estimates.

      given the state of the economy I bet you'll get it cheaper than i did (plus prices will vary by area, I know I paid a bit more than one of our clients did in upstate NY)

      For a frame of reference, could you give me an idea of what you had to pay per sq foot? feel free to IM me.


    21. Member DiscoStu's Avatar
      Join Date
      May 8th, 2001
      Location
      MA
      Posts
      5,993
      Vehicles
      2010/VW/Passat - 2009/VW/Jetta/Sportwagen
      03-30-2009 02:57 PM #21
      I had quotes of $2 to $2.25 per sq. ft. for 6" of open cell foam.

    22. Member InSaNeBoY's Avatar
      Join Date
      Feb 16th, 1999
      Location
      Topsham, ME
      Posts
      2,027
      Vehicles
      VW
      03-30-2009 02:57 PM #22
      Quote, originally posted by thesteve »

      For a frame of reference, could you give me an idea of what you had to pay per sq foot? feel free to IM me.

      sorry, I'm a lazy bastard. don't feel like measuring my house and calculating the square footage of the insulated areas to find out the cost.

      ClubDub is back!!!
      2003 VW Passat Wagon
      2003 VW Jetta Wagon TDi

    23. 03-30-2009 03:20 PM #23
      Quote, originally posted by DiscoStu »
      I had quotes of $2 to $2.25 per sq. ft. for 6" of open cell foam.

      Okay. That gives me somewhere to start.


    24. 03-30-2009 03:20 PM #24
      Quote, originally posted by InSaNeBoY »

      sorry, I'm a lazy bastard. don't feel like measuring my house and calculating the square footage of the insulated areas to find out the cost.

      Totally understand.


    Posting Permissions

    • You may not post new threads
    • You may not post replies
    • You may not post attachments
    • You may not edit your posts
    •